Field
The subject matter disclosed herein relates to acquisition and processing of inertial sensor data for a mobile device.
Information
Movement of a mobile device may be tracked to determine a position, orientation, and velocity of the mobile device at a particular point in time. If acceleration or movement of a mobile device about three coordinate axes can be determined and measured, such information may be utilized to estimate a current position, orientation, and velocity. Such coordinate axes may be orthogonal with respect to each other and may be utilized to represent a three-dimensional space.
In order to precisely estimate position, orientation, and velocity, it may be useful to measure linear acceleration and/or rotation rate along or about one or more coordinate axes. A precise determination may be made if sensor measurements from a plurality of sensors are processed at the same time. If analog sensors are utilized, analog output signals from such analog sensors may be converted to a digital format by, for example, an analog-to-digital conversion before additional processing. A particular analog sensor may generate a raw signal which is responsive to acceleration, and may filter such a raw signal before providing an analog signal for further processing. Different sensors may utilize filters having different associated processing delays. For example, an accelerometer may generate a raw signal and then spend 1.0 microsecond, for example, to filter such a raw signal before outputting an analog signal. A gyroscope, on the other hand, might generate a raw signal and then filter such a raw signal for a different amount of time such as, for example, 1.5 microseconds. Accordingly, in the example above, upon sensing a physical event representing itself as simultaneous acceleration and rotation of a device, such an accelerometer may output an analog signal 0.5 microseconds prior to a time at which such a gyroscope outputs an analog signal based on the same detected physical event.